1. Field of the Invention
The present invention relates to supports for gas chromatography comprising aggregates of finely divided carbon particles usable for a wide range of analyses particularly including an analysis of an aqueous solution containing a high-boiling component, and to a process for preparing the same.
2. Prior Art
Supports prepared by sintering natural diatomaceous earth and then treating the sinter with an acid and a silanizing agent have widely been used as those for gas chromatography.
This is because the diatomaceous earth has a large capability of supporting a liquid phase thereon and a small adsorptivity (adsorption capability).
Further, in recent years, carbon type supports have come to be used as well.
The carbon type supports comprise carbon as the base material and therefore have features unattainably by the diatomaceous earth type supports, such as good chemical stability, excellent resistance to heat, water and chemicals and strength superior to that of the diatomaceous earth, and further have an advantage that the variations in one lot and among different lots are very small.
However, since the diatomaceous earth is a natural product, it is disadvantageous in that it brings about a wide variation, lacks the reproducibility between lots, is susceptible to hydrolysis, brings about cracking due to hydrolysis, and develops new adsorption sites, which lowers the performance. Further, it has drawbacks such that the upper limit of the heat resistance is as low as 325.degree. to 350.degree. C. for the diatomaceous earth treated with an inert acid and a silanizing agent.
On the other hand, the carbon type supports have a drawback that in the case of, for example, activated carbon or a heat-treated porous thermosetting resin, the adsorptivity is unfavorably excessively large because most of the pores have a diameter of 1,000 .ANG. or less.
Thus, the conventional supports are not satisfactory for use in gas chromatography, and therefore the development of novel supports for gas chromatography having a low adsorptivity, no variation and excellent heat resistance has been desired in the art.